How to identify and treat Manna Gum Eucalyptus disease?

Cherry

our Manna Gum in local small town, Gippsland has been eaten by something. How do I treat it? It is only young and don’t feel it will survive if I don’t.

JacobZ

Hi @Cherry,

I’d say it is quite likely the insects or growths shown in your first image are playing a major role, but I’m struggling to identify them clearly from the photos.

Would it be possible to share a few more close-up photos of the insects, the underside of the leaves, and any other growths or marks on the tree?

It does look similar to the type of damage @Aleisha124 identified as sawfly-related in this discussion, but the insects in your photos don’t appear to be sawflies:

https://www.workshop.bunnings.com.au/discussion/280519/how-to-treat-eucalyptus-leaves-covered-in-brown-spots

At this stage, I’d avoid applying any insecticide until the pest is properly identified. For now, I’d suggest physically removing as much of the insects and associated growth using a gloved hand.

You can also support the tree’s recovery by keeping it well watered through dry periods and applying mulch around the base.

Allow me to tag some of our knowledgeable gardeners @Noelle, @mich1972 and @robchin to see if they can help to identify these insects and offer insight on the best steps moving forward.

When we can identify those insects, we can certainly look if there is an insecticide that will help.

Jacob